Hello everyone, I know this is kind of a dumb question, but I am using an Arduino mega and I want to connect an I2C LCD display to it. Problem is, there are two sets of SDA and SCL pins. Communication SDA and SCL, and then Digital (PWM -) SDA and SCL pins. So I was wondering which sets of SDA and SCL pins should I use for my lCD?
Thanks, Psidle
Are you talking about pins 20 and 21 vs. the two pins on the header next to the AREF pin? If so, you can use either. They are electrically connected the same. The reason why there is the redundant breakout of these next to the AREF pin is because on the Uno they are on A4/A5, on the Leonardo they are on 2 and 3, on the Mega they are on 20 and 21. So this made it difficult for someone to produce a shield that uses I2C communication that would be compatible with Uno, Leonardo, and Mega. But now that there is a dedicated location for SDA/SCL on all boards, it's possible to do this.
Alright, Thank you so much!
pert:
you can use either.
And may be just worth pointing out to OP that they can actually use both, that is at the same time: I2C being a bus (and apologies OP if you know this already) you can have loads of peripherals connected. If you need 2, then both sets of pins is a handy way of achieving that; of course if you need more, you need to make your own bus connections on breadboard or similar.